A known shear accessory for a rotary power tool comprises an accessory housing, shearing blades an input shaft, and transmission coupled to the input shaft and the blades to convert rotary motion of the input shaft to shearing motion of the blades. The input shaft is received in a tool holder of a power tool and is driven in rotation by the power tool to cause shearing motion of the blades. Without sufficient support, the accessory housing will tend to rotate along with the input shaft. Therefore, in one design, the accessory housing may include an external handle to be grasped by the user. However, this makes one handed operation of the tool virtually impossible. Other designs include a brace that can clamp the accessory housing to the power tool housing. However, known braces tend to be bulky, expensive, and difficult to attach and maneuver.